Bicycle hub

ABSTRACT

A bicycle hub is provided that comprises a tubular hub axle, a hub body, a bearing and a clearance adjusting member. The bearing includes an outer ring coupled to the hub body, an inner ring coupled to the hub axle, and a plurality of rolling components disposed between the outer ring and the inner ring. The clearance adjusting member is disposed with respect to the outer ring of the bearing such that at least a portion of the clearance adjusting member is disposed axially inwardly of the outer ring. The clearance adjusting member is configured and arranged to prevent a grease inside the bearing to leak toward an axially inward direction of the hub axle with a prescribed radial clearance being maintained between the clearance adjusting member and one of the hub axle and the outer ring of the bearing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2004-044937. The entire disclosure of Japanese Patent Application No. 2004-044937 is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a bicycle hub mounted to a bicycle frame.

2. Background Information

Official Gazette for Kokai Utility Model No. S52-60062 discloses a conventional bicycle hub installed in the central portion of a wheel of a bicycle comprises a hub axle, a hub body and a pair of bearings. The hub axle is non-rotatably mounted to a frame of the bicycle (for example, to a front-fork). The hub body is coaxially coupled to the hub axle so that the hub body is disposed radially outwardly with respect to the hub axle. The bearings are configured and arranged to support the hub body so that the hub body can freely rotate around the hub axle. The outer peripheral surface of the hub axle includes a pair of male screw sections in axial ends thereof so that the hub is mounted to the frame by a pair of nuts that are screw on axial ends of the male screw of the hub axle. The bearings are angular-type bearings. Each of the bearings is provided with an outer ring, an inner ring, and a plurality of rolling components. The outer ring is disposed along an inner peripheral surface of the hub body and includes a ball receiving surface. The inner ring is screwed into the hub axle and includes a ball pushing surface. The rolling components are disposed between the outer ring and the inner ring at predetermined intervals in a circumferential direction of the hub.

The inner portion of each of the bearings is filled with grease in order to make the rotation of the bearings smooth. The ball receiving surface of the outer ring is arranged as a concaved surface that faces toward a generally axial outward direction of the hub axle. The ball pushing surface of the inner ring is arranged as a concaved surface that faces toward a generally axial inward direction of the hub axle. The angular-type ball bearing installed on the hub is designed to maintain a certain degree of clearance or gap between the radial innermost peripheral surface of the outer ring and an outer peripheral surface of the hub axle. Moreover, a sealing component is coupled to an outer axial direction of the bearing. Therefore, the bearing is designed so that the grease does not leak towards the outer axial direction of the bearing.

However, since there is the clearance between the outer ring and the hub axle in at an axial inner position of the bearing, the grease filled within the bearing occasionally leaks towards the inner axial direction of the bearing. Especially when the hub includes the male screw section is formed in the same screw direction along the entire surface of the outer peripheral surface of the hub axle, the male screw acts like a pump due to the rotation of the wheel (i.e., the rotation of the outer ring of the bearing) relative to the hub axle. Consequently, the grease flows out form the bearing toward the inner axial direction of the hub axle. For example, in a case in which the male screw is a right-handed screw, in the bearing on the right side as viewed from the rear side of the bicycle, when the wheel rotates in the direction of travel, the grease tends to flow out toward the inner axial direction of the hub axle. When the grease flows out from the bearing toward the inner axial direction of the hub axle, the grease tends to travel toward a relatively larger space behind the outer ring and retained in that space due to the centrifugal force. In such a case, the amount of the grease in the bearing becomes insufficient, and rotation of the wheel deteriorates.

In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved bicycle hub. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.

SUMMARY OF THE INVENTION

One object of the present invention is to prevent grease from flowing out from the bearing toward the inner axial direction.

In order to achieve the above mentioned object and other objects of the present invention, a bicycle hub is provided that comprises a tubular hub axle, a hub body, a first bearing and a clearance adjusting member. The tubular hub axle is configured and arranged to be non-rotatably coupled to a bicycle. The hub body is coaxially coupled on the hub axle so that the hub body is disposed radially outwardly with respect to the hub axle. The first bearing is disposed between the hub body and the hub axle so that the hub body freely rotates with respect to the hub axle. The first bearing includes a first outer ring, a first inner ring and a plurality of first rolling components. The first outer ring is coupled to the hub body. The first inner ring is non-rotatably coupled to the hub axle in a position with respect to the first outer ring so that the first inner ring faces the first outer ring. The first rolling components are installed between the first outer ring and the first inner ring. The clearance adjusting member is disposed with respect to the first outer ring of the first bearing such that at least a portion of the clearance adjusting member is disposed axially inwardly of the first outer ring. The clearance adjusting member is configured and arranged to prevent a grease inside the first bearing to leak toward an axially inward direction of the hub axle with a prescribed radial clearance being maintained between the clearance adjusting member and one of the hub axle and the first outer ring of the first bearing.

These and other objects, features, aspects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of this original disclosure:

FIG. 1 is an overall right side elevational view of a bicycle provided with a front hub and a rear hub in accordance with a first embodiment of the present invention;

FIG. 2 is a partial cross sectional view of the front hub in accordance with the first embodiment of the present invention;

FIG. 3 is a partial cross sectional view of the rear hub in accordance with the first embodiment of the present invention;

FIG. 4 is a partial cross sectional view of a bicycle hub in accordance with a second embodiment of the present invention;

FIG. 5 is a partial cross sectional view of a bicycle hub in accordance with a third embodiment of the present invention;

FIG. 6 is a partial cross sectional view of a bicycle hub in accordance with a fourth embodiment of the present invention;

FIG. 7 is a partial cross sectional view of a bicycle hub in accordance with a fifth embodiment of the present invention; and

FIG. 8 is a partial cross sectional view of a bicycle hub in accordance with the fifth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Selected embodiments of the present invention will now be explained with reference to the drawings. It will be apparent to those skilled in the art from this disclosure that the following descriptions of the embodiments of the present invention are provided for illustration only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

Referring initially to FIG. 1, a bicycle 101 with a front hub 10 and a rear hub 12 is illustrated in accordance with a first embodiment of the present invention. As seen in FIG. 1, the bicycle 101 is arranged as a road racer. The bicycle 101 includes a diamond-shaped frame 102, a handle 104, a drive unit 105, a pair of front and rear wheels 106 and 107. The frame 102 comprises a front fork 98. The handle 104 is fixedly coupled to the front fork 98. The drive unit 105 basically comprises a chain, pedals, a derailleur, front and rear sprockets, and other conventional parts. The front and rear wheels 106 and 107 are coupled to the front fork 98 and the rear portion of the frame 102. Each of the front and rear wheels 106 and 107 includes a plurality of spokes 99. Moreover, the front and rear wheels 106 and 107 are provided with a front brake 108 and rear brake 109, respectively. The front hub 10 is coupled to a center potion of the front wheel 106, and the rear hub 12 is coupled to a center portion of the rear wheel 107.

As shown in FIG. 2, the front hub 10 basically comprises a hub axle 20, a hub body 21, and a pair of left and right bearings 22 a and 22 b. The hub axle 20 is configured to be freely attachable to or detachable from a pair of right and left fork end portions 98 a that are disposed in the lower end of the front fork 98. The hub body 21 is coaxially disposed radially outwardly with respect to the hub axle 20. The left bearing 22 a and the right bearing 22 b are disposed between the hub axle 20 and the hub body 21 at axial end portions of hub body 21 as seen in FIG. 2.

The hub axle 20 of the front hub 10 is arranged as a quick release lever type hub axle, which basically comprises a hollow axle body 23, a quick hub rod 24, an adjusting nut 25, a and a cam lever 26. The axle body 23 has a right handed male screw section 23 a extending along the entire surface of the outer peripheral surface thereof. The quick hub rod 24 penetrates through the axle body 23 with the adjusting nut 25 screwed on one axial end thereof. The cam lever 26 is coupled to the other axial end of the quick hub rod 24. As seen in FIG. 2, a pair of volume springs 36 a and 36 b are coupled between the one end of the axle body 23 (right end of FIG. 2) and the adjusting nut 25, and between the other end of the axle body 23 (left end of FIG. 2) and the cam lever 26.

The hub body 21 of the front hub 10 has a generally tubular shape and is, for example, made of aluminum alloy. The hub body 21 includes a pair of hub flanges 30 a and 30 b as seen in FIG. 2 and the spokes 99 are latched on the radial end portions of the outer perimeters of the hub flanges 30 a and 30 b. The hub body 21 further includes a pair of bearing mounting sections 21 a and 21 b in axial end portions thereof for mounting the left bearing 22 a and the right bearing 22 b, respectively.

The left bearing 22 a basically comprises a left outer ring or cup 31 a, a left inner ring or cone 32 a and a plurality of rolling components 33 a (only one left rolling component 33 a is shown in FIG. 2). Similarly, the right bearing 22 b comprises a right outer ring 31 b, a right inner ring 32 b and a plurality of rolling components 33 b (only one right rolling component is shown in FIG. 2). The left outer ring 31 a of the left bearing 22 a and the right outer ring 31 b of the right bearing 22 b are pressed into the bearing mounting sections 21 a and 21 b of the hub body 21, respectively, which are formed on the inner perimeter in the axial end portions of the hub body 21. The left outer ring 31 a includes a ball receiving surface 31 c that faces in a generally axial outward direction. The right outer ring 31 b includes a ball receiving surface 31 d that faces in a generally axial outward direction. The left inner ring 32 a includes a ball pushing surface 32 c that faces in a generally axial inward direction. The right inner ring 32 b includes a ball pushing surface 32 d that faces in a generally axial inward direction. Therefore, the left bearing 22 a and the right bearing 22 b are arranged as angular ball bearings, in which the load capacity relative to the thrust direction is greater. The left inner ring 32 a and the right inner ring 32 b are screwed into the male screw section 23 a, which is formed on the outer peripheral surface of the axle body 23 of the hub axle 20. The axial positions of the left inner ring 32 a and the right inner ring 32 b are locked by a pair of lock nuts 35 a and 35 b that are installed in contact with the axial end surfaces of the left inner ring 32 a and the right inner ring 32 b, respectively. Therefore, the left inner ring 32 a and the right inner ring 32 b are not movable in the axial direction. The front hub 10 includes a pair of sealing components 39 a and 39 b that are disposed in the outer axial end portions of the left bearing 22 a and the right bearing 22 b, respectively.

Moreover, in the front hub 10 of this embodiment, a clearance adjusting member 37 a is provided between the radial inner surface of the left outer ring 31 a, which is closest to the axle body 23, and the outer peripheral surface of the axle body 23 of the hub axle 20. Likewise, a clearance adjusting member 37 b is provided between the radial inner surface of the right outer ring 31 b, which is closest to the axle body 23, and the outer peripheral surface of the axle body 23 of the hub axle 20. In this first embodiment, each of the clearance adjusting members 37 a and 37 b preferably comprises three O-rings 38 that are arranged on the outer peripheral surface of the axle body 23. More specifically, the three O-rings 38 are arranged side by side in a direction toward the axial inner portion of the axle body 23 as one of the O-rings 38 abuts against the axial inner end surface of the left or right inner ring 32 a and 32 b as seen in FIG. 2. The clearance adjusting members 37 a and 37 b are configured such that a minimum clearance or gap between the radial outer most surface of the clearance adjusting members 37 a and 37 b and the radial inner surface of the left outer ring 31 a and the right outer ring 31 b is set to, for example, approximately 0.4 mm.

With the front hub 10 in the first embodiment as described above, the clearance or gap between the axle body 23 and the left outer ring 31 a or the right outer ring 31 b in the radial direction of the hub axle 20 is narrowed by providing the clearance adjusting members 37 a and 37 b between the axle body 23 of the hub axle 20 and the left and right outer rings 31 a and 31 b. At the same time, the grease contained inside the left bearing 22 a and the right bearing 22 b is less likely to leak toward the inner axial direction of the hub axle 20. In particular, when the clearance adjusting members 37 b is not provided in the right bearing 22 b shown in the right side of FIG. 2, when the front wheel 106 rotates in the direction of travel, the grease tends to leak out from the right bearing 22 b with the male screw section 23 a acting as the pump. However, by installing the clearance adjusting member 37 b as seen in FIG. 2, the clearance between the right outer ring 31 b and the hub axle 20 is narrowed. Consequently, the grease is less likely to leak in the inner axial direction of the hub axle 20 and more likely to be retained within the right bearing 22 b. In addition, because there is the clearance (approximately 0.4 mm) between the clearance adjusting members 37 a and 37 b and the left outer ring 31 a and the right outer ring 31 b, respectively, the deterioration of rotational performance of the left and right bearings 22 a and 22 b, such as heavy rotation, can be prevented.

As shown in FIG. 3, the rear hub 12 basically comprises a hub axle 40, a hub body 41, a pair of left and right bearings 42 a and 42 b and a freewheel 43. The hub axle 40 is freely attachable to or detachable from a pair of right and left fork end portions 102 a disposed on the rear of the frame 102. The hub body 41 is coaxially disposed radially outwardly with respect to the hub axle 40. The left bearing 42 a and the right bearing 42 b are disposed between the hub axle 40 and the hub body 41 in one axial end portion of the hub body 41. The freewheel 43 is coupled to the axial end portion of the hub body 41 where the right bearing 42 b is coupled to. The freewheel 43 is configured to be coupled to the drive unit 105 on the outer perimeter thereof. The freewheel 43 is also configured to be non-rotatably coupled to a multiple-layer sprockets 111 (e.g., 10 sprockets as shown in a dotted line in FIG. 3).

The hub axle 40 of the rear hub 12 is, for example, a quick release type hub axle, which basically comprises a hollow axle body 44 with a pair of right-handed male screw sections 44 a and 44 b on the outer peripheral surface thereof. The male screw section 44 a is arranged to extend from a portion located slightly inside of the portion to which the left bearing 42 a is mounted toward the outward axial direction. The male screw section 44 b is arranged to extend from a portion located slightly inside of the portion to which the freewheel 43 is mounted toward the outward axial direction. The structure of the hub axle 40 is basically identical to that of the hub axle 20 of the front hub 10 except for the male screw sections 44 a and 44 b and the length of the hub axle. Therefore, the structure of the hub axle 40 will not be discussed in detail herein for the sake of brevity.

The hub body 41 of the rear hub 12 preferably includes a hub main body portion 45 and a power transmission member 46. The hub main body portion 45 has a generally tubular shape and is made of aluminum alloy. The hub main body portion 45 is provided with a pair of hub flanges 50 a and 50 b on the outer peripheral surface thereof, and the spokes 99 are latched on the radial end portions of the hub flanges 50 a and 50 b. The power transmission member 46 is non-rotatably coupled to the hub main body portion 45. The hub main body portion 45 further includes a bearing mounting section 45 a in the one axial end thereof (left end of FIG. 3) where the left bearing 42 a is coupled to. Moreover, the hub main body portion 45 has a step section 45 b in the inner peripheral surface thereof at a portion adjacent to the right axial end of the hub main body portion 45. The step section 45 b is configured and arranged to be coupled to a clearance adjusting member 57.

The power transmission member 46 is preferably a generally cylindrical steel component with a step structure. The inner peripheral surface of the power transmission member 46 in one axial end (left end of FIG. 3) is non-rotatably coupled to the right axial end of the hub main body portion 45 (right end of FIG. 3) by a serrated connection or the like. The power transmission member 46 is fixedly coupled to the hub main body portion 45 by a cylindrical bolt 47, which passes through the inner perimeter of the right axial end portion of the hub main body portion 45 while screwed into the inner perimeter of the hub main body portion 45. The power transmission member 46 has a bearing mounting section 46 a on the outer peripheral surface of the right axial end of the power transmission member 46. The right bearing 42 b is screwed into the bearing mounting section 46 formed on the power transmission member 46. The power transmission member 46 further includes a clutch mounting recess 46 b on the outer peripheral surface thereof, which is disposed axially inwardly with respect to the bearing mounting section 46 a. The clutch mounting recess 46 b is configured and arranged to be coupled to a one-way clutch 61 as seen in FIG. 4. Furthermore, the power transmission member 46 forms an inner ring portion disposed axially inwardly with respect to the clutch mounting recess 46 b on the outer peripheral surface of the power transmission member 46. The inner ring portion of the power transmission member 46 is configured to serve as an inner ring for a first freewheel bearing 63 that is used for supporting the freewheel 43 so that the freewheel 43 freely rotates around the power transmission member 46.

In the structure of the rear hub 12 described above, the cylindrical bolt 47 and the axle body 44 are arranged such that a clearance or gap between the inner peripheral surface of the cylindrical bolt 47 and the outer peripheral surface of the axle body 44 is set to a substantially small value, for example, approximately 0.4 mm. Therefore, the grease leakage from the right bearing 42 b toward the axial inner direction is not very problematic.

The left bearing 42 a of the rear hub 12 basically comprises a left outer ring or cup 51 a, a left inner ring or cone 52 a and a plurality of generally spherical shaped rolling components 53 a (only one rolling component 53 a is shown in FIG. 3). The right bearing 42 b basically comprises a right outer ring 51 b, a right inner ring 52 b and a plurality of generally spherical shaped rolling components 53 b (only one rolling component 53 b is shown in FIG. 3). The left outer ring 51 a is pressed into the bearing mounting section 45 a formed on the hub main body portion 45 as seen in FIG. 3. The right bearing 42 a is pressed into and attached to the bearing mounting section 46 a formed on the power transmission member 46. The right outer ring 51 b of the right bearing 42 b also includes an inner ring portion that is configured to serve as an inner ring for a second freewheel bearing 64. The second freewheel bearing is configured and arranged to support the freewheel 43 so that the freewheel 43 freely rotates.

The left outer ring 51 a includes a ball receiving surface 51 c that faces in a generally axially outward direction of the hub axle 44. The left inner ring 52 a includes a ball pushing surface 52 c that faces in a generally axially inward direction of the hub axle 44. The right outer ring 51 b includes a ball receiving surface 51 d that faces in a generally axially outward direction of the hub axle 44. The right inner ring 52 b includes a ball pushing surface 52 d that faces in a generally axially inward direction of the hub axle 44. Thus, similarly to the left and right bearings 22 a and 33 b of the front hub 10, the left and right bearings 42 a and 42 b are arranged as the angular ball bearings, in which the load capacity relative to the thrust direction becomes greater. The left inner ring 52 a and the right inner ring 52 b are screwed into the male screw sections 44 a and 44 b, respectively, which are formed on the axle body 44 of the hub axle 40 as seen in FIG. 3.

The axial positions of the first Inner ring 52 a and the right inner ring 52 b are locked by the lock nuts 55 a and 55 b, which are installed in contact with the axial outer surface of the left inner ring 52 a and the right inner ring 52 b, respectively. Therefore, the left inner ring 52 a and the right inner ring 52 b are not movable in the axial direction with respect to the hub body 41. A sealing component 59 is coupled to the axial outer end portion the left bearing 42 a. Therefore, the grease contained in the left bearing 42 a is less likely to leak from the left bearing 42 a toward the axial outward direction.

The clearance adjusting member 57 is disposed on the radial innermost surface of the left outer ring 51 a, which is closest to the outer peripheral surface of the hub axle 40. In this first embodiment, the clearance adjusting member 57 used in the rear hub 12 is arranged as a tubular member 58 with a first axial end (left side end in FIG. 3) of the tubular member 58 is coupled to the radial innermost surface of the left outer ring 51 a, and a second axial end (right side end in FIG. 3) of the tubular member 58 is coupled to the step section 45 b of the hub main body portion 45. More specifically, the first axial end of the tubular member 58 is coupled to the radial innermost surface of the left outer ring 51 a such that a certain degree of clearance is maintained between the tubular member 58 and the hub axle 40. The tubular member 58 is preferably arranged such that the diameter of the second axial end of the tubular member 58 is larger than the diameter of the first axial end of the tubular member 58, and the diameter of the tubular member 58 gradually becomes larger from the first axial end toward the second axial end in a tapered manner. The clearance between the radial innermost peripheral surface at the first axial end of the tubular member 58 and the male screw section 44 a formed on the axle body 44 of the hub axle 40 is preferably set to a substantially small value, e.g., approximately 0.4 mm.

As seen in FIG. 3, the freewheel 43 is provided with a sprocket mounting section 60 a, a drive unit 60, and the one-way clutch 61. The sprocket mounting section 60 a is formed in the outer peripheral surface of the freewheel 43 for mounting the multiple-layer sprocket 111. The drive unit 60 is supported by the outer perimeter of the power transmission member 46 so that the drive unit 60 freely rotates around the power transmission member 46. More specifically, the drive unit 60 is supported by the first freewheel bearing 62 and the second freewheel bearing 63 such that the drive unit 60 freely rotates around the power transmission member 46. The one-way clutch 61 is disposed between the drive unit 60 and the power transmission member 46 to transmit only the rotation of the direction of travel of the drive unit 60 to the power transmission member 46. The one-way clutch 61 is a fork end type clutch coupled to the clutch mounting recess 46 b of the power transmission member 46 so that it freely swings and transmits the rotation of the drive unit 60 to the power transmission member 46.

The clearance between the drive unit 60 and the hub axle 40, and the clearance between the drive unit 60 and the power transmission member 46, are sealed by a pair of sealing components 66 and 67. Therefore, the grease inside the bearings is unlikely to leak to the outside of the freewheel 43.

Accordingly, similarly to the front hub 10, with the rear hub 12 of the first embodiment as described above, the clearance between the left outer ring 51 a and the axle body 44 of the hub axle 40 in the radial direction is narrowed by providing the clearance adjusting member 57 on the radial innermost peripheral surface of the left outer ring 51 a. Therefore, the grease contained inside the left bearing 42 a is less likely to leak toward the axial inner direction of the hub axle 40. In particular, when the clearance adjusting member 57 is not provided with the left bearing 42 a shown on the left side of FIG. 3, the grease inside the left bearing 42 a tends to leak in the direction toward the axial outer portion (toward left side of FIG. 3) when the rear wheel 107 rotates in the direction of travel as the right-handed male screw section 44 a acting as the pump. Thus, in the first embodiment of the present invention, the grease is further prevented from leaking toward the inner axial direction (toward right of FIG. 3). Since the clearance adjusting member 57 is disposed between the left outer ring 51 a and the hub axle 40, the grease leakage from the left bearing 42 a that is disposed on an axial side of the hub axle 40 that is opposite from where the freewheel 43 is mounted can be prevented. Moreover, since the male screw section 44 a is a right-handed screw, the pump effect of the male screw section 44 a of the hub axle 40 is utilized to further prevent leakage from the left bearing 42 a.

In the first embodiment of the present invention, the clearance adjusting member 57 is arranged such that a right axial end portion thereof has a larger diameter than a left axial end portion thereof, and the diameter of the clearance adjusting member is gradually increased from the left axial end portion to the right axial end portion in a tapered manner as seen in FIG. 3. Therefore the clearance adjusting member 57 can be supported by the radial inner surface of the hub body 41 at the step section 45 b.

With the first embodiment of the present invention, since the clearance can be adjusted by mounting the O-rings 38 utilizing the convex/concave nature of the male screw section 23 a, the structure of the clearance adjusting member 37 is simplified. In addition, by arranging a plurality of O-rings 38 side by side in a line, the effects of preventing the leakage of the grease can be further increased.

Second Embodiment

Referring now to FIG. 4, a front hub 110 in accordance with a second embodiment will now be explained. In view of the similarity between the first and second embodiments, the parts of the second embodiment that are identical to the parts of the first embodiment will be given the same reference numerals as the parts of the first embodiment. Moreover, the descriptions of the parts of the second embodiment that are identical to the parts of the first embodiment may be omitted for the sake of brevity.

The front hub 110 of the second embodiment is basically identical to the front hub 10 of the first embodiment illustrated in FIG. 2 except that O-rings 38 used as the clearance adjusting members 37 a and 37 b are substituted with the cylindrical members 138 used as clearance adjusting members 137 a and 137 b as shown in FIG. 4. More specifically, in the second embodiment, the cylindrical members 138 are used as the clearance adjusting members for the left and right bearings 22 a and 22 b. The cylindrical members 138 are preferably made of a material with heat contraction properties such as synthesized resin with heat contraction properties. In the second embodiment, the cylindrical members 138 are mounted to the outer peripheral surface of the axle body 23 of the hub axle 20 at positions that face the left outer ring 31 a and the right outer ring 31 b as seen in FIG. 4. In this embodiment as well, the clearance between the left outer ring 31 a and the right outer ring 31 b and the male screw section 23 a of the axle body 23 is narrowed by providing the clearance adjusting members 137 a and 137 b on the male screw section 23 a. Similarly to the first embodiment, the clearance adjusting members 137 a and 137 b are configured such that a minimum clearance or gap between the radial outer most surface of the clearance adjusting members 137 a and 137 b and the radial inner surface of the left outer ring 31 a and the right outer ring 31 b is set to, for example, approximately 0.4 mm.

In the second embodiment of the present invention, since the clearance adjusting members 137 a and 137 b are made of a material with heat contraction properties, the clearance adjusting members 137 a and 137 b can be easily mounted onto the hub axle 20 simply by mounting the clearance adjusting members 137 a and 137 b onto the hub axle 20 and heating them.

Third Embodiment

Referring now to FIG. 5, a front hub 210 in accordance with a third embodiment will now be explained. In view of the similarity between the first and third embodiments, the parts of the third embodiment that are identical to the parts of the first embodiment will be given the same reference numerals as the parts of the first embodiment. Moreover, the descriptions of the parts of the third embodiment that are identical to the parts of the first embodiment may be omitted for the sake of brevity.

The front hub 210 of the third embodiment shown in FIG. 5 is basically identical to the front hub 20 of the first embodiment except for the clearance adjusting members 37 a and 37 b of the first embodiment are substituted by a clearance adjusting member 237. The clearance adjusting member 237 is preferably arranged as a cylindrical member 238 that is made of a material such as synthesized resin or metal. The cylindrical member 238 is configured as a one-piece member that extends between the left outer ring 31 a of the left bearing 22 a and the right outer ring 31 b of the right bearing 22 b. More specifically, the cylindrical member 238 includes a left engaging portion 237 a, a right engaging portion 237 b, and a cylindrical body portion 237 c. The left engaging portion 237 a is coupled to the radial innermost surface of the left outer ring 31 a, and the right engaging portion 237 b is coupled to the radial innermost surface of the right outer ring 31 b as seen in FIG. 5. The cylindrical body portion 237 c extends between the left engaging portion 237 a and the right engaging portion 237 b. With the front hub 210 of the third embodiment, the radial clearance between the male screw section 23 a formed on the axle body 23 and the left outer ring 31 a or is narrowed by mounting the clearance adjusting member 237 to the left outer ring 31 a and Second Outer ring 31 as seen in FIG. 5. The clearance adjusting member 237 is configured such that a minimum clearance or gap between the radial inner most surface of the clearance adjusting member 237 and the male screw section 23 a formed on the axle body 23 of the hub axle 20 is set to, for example, approximately 0.4 mm

In the third embodiment of the present invention, since the clearance adjusting member 237 is formed as a one-piece member with the left and right engaging portions 237 a and 237 b coupled to the radial inner surfaces of the left and right outer rings 31 a and 31 b, the leakage of grease can be prevented. Moreover, since the hub axle 20 is covered by the clearance adjusting member 237 between the let and right outer rings 31 a and 31 b, even when the grease leaks from the left and/or right bearings 22 a and 22 b, the grease is prevented from adhering to the back side of the left and/or right outer rings 31 a and 31 b. Therefore, the amount of grease leakage is decreased.

Fourth Embodiment

Referring now to FIG. 6, a front hub 310 in accordance with a fourth embodiment will now be explained. In view of the similarity between the third and fourth embodiments, the parts of the fourth embodiment that are identical to the parts of the third embodiment will be given the same reference numerals as the parts of the third embodiment. Moreover, the descriptions of the parts of the fourth embodiment that are identical to the parts of the third embodiment may be omitted for the sake of brevity.

The front hub 310 of the fourth embodiment shown in FIG. 6 is basically identical to the front hub 210 of the third embodiment except that the clearance adjusting member 237 of the third embodiment is substituted by a clearance adjusting member 337 in the fourth embodiment. More specifically, the clearance adjusting member 337 of the fourth embodiment differs from the clearance adjusting member 237 of the third embodiment in that the clearance adjusting member 337 includes a right-handed female screw section 337 d on the inner peripheral surface thereof which is adjacent to the right bearing 22 b. More specifically, the female screw section 337 d is arranged to extend on the inner peripheral surface of the clearance adjusting member 337 from the right side portion of the cylindrical body portion 337 b to the right engaging portion 337 b. The female screw section 337 d is configured and arranged such that the pumping effect of the female screw section 337 d counteracts the pumping effect of the male screw section 23 a formed on the axle body 23 of the hub axle 20. Alternatively, the female screw section 337 d can be configured and arranged such that the pumping effect of the female screw section 337 d exceeds the pumping effect of the male screw section 23 a to generate a flow toward the axial outward direction against the pumping effect of the male screw section 23 a. Therefore, in the fourth embodiment of the present invention, the leakage of the grease from the right bearing 22 b toward the axial inner direction is further decreased.

In the fourth embodiment of the present invention, the pump effect of the female screw section 337 d counter act or overcome the pump effect of the male screw section 23 a on the right side of the hub axle 20 when facing the direction of travel of the bicycle. Thus, the grease leakage can be further prevented.

Fifth Embodiment

Referring now to FIGS. 7 and 8, a front hub 410 and a rear hub 412 in accordance with a fifth embodiment will now be explained. In view of the similarity between the first and fifth embodiments, the parts of the fifth embodiment that are identical to the parts of the first embodiment will be given the same reference numerals as the parts of the first embodiment. Moreover, the descriptions of the parts of the fifth embodiment that are identical to the parts of the first embodiment may be omitted for the sake of brevity.

The front hub 410 of the fourth embodiment differs from the bicycle hub 10 of the first embodiment in that a pair of male screw sections 420 a and 420 b are formed in only axial end portions of the hub axle 420 where left and right inner rings 432 a and 432 b of the left and right bearings 422 a and 422 b are coupled to as seen in FIG. 7, instead of having the male screw section 23 a extending across the entire outer peripheral surface of the hub axle 20 as seen in FIG. 2. Thus, in this embodiment of the present invention, the front hub 410 is provided with a left clearance adjusting member 437 a and a right clearance adjusting member 437 b that are mounted to the inner perimeter of a hub body 421 such that the left and right clearance adjusting members 437 a and 437 b abut against the axial inner surface of left and right outer rings 431 a and 431 b of the left and right bearings 422 a and 422 b, respectively.

Each of the left clearance adjusting member 437 a and the right clearance adjusting member 437 b are arranged as a cylindrical member with a flange. More specifically, the left and right clearance adjusting members 437 a and 437 b include first and second flange portions 437 c and 437 d, and first and second cylindrical body portions 437 e and 437 f, respectively. The first and second flange portions 437 c and 437 d of the left and right clearance adjusting member 437 a and 437 b are configured to have a larger maximum diameter than the first and second cylindrical portions 437 e and 437 f, respectively. The first and second flange portions 437 c and 437 d are mounted to the inner perimeter of the hub body 421, and abut against the axial inner surfaces of the left outer ring 431 a and the right outer ring 431 b, respectively. The first and second cylindrical body portions 437 e and 437 f of the left and right clearance adjusting members 437 a and 437 b extend from the radial inner portion of the first flange portion 437 c and the second flange portion 437 d, respectively, toward the inner axial inner direction. The first and second cylindrical body portions 437 e and 437 f are supported by the inner perimeter of the hub body 21, which has been reduced in diameter. As seen in FIG. 7, the radial innermost portion of the first flange portion 437 c and the second flange portion 437 d protrude radially inwardly comparing to the first and second cylindrical body portions 437 e and 437 f. The clearance adjusting members 437 a and 437 b are configured such that a clearance or gap between the radial inner most surface of the first flange portion 437 c and the second flange portion 437 d of the clearance adjusting members 437 a and 437 b and the radial outer peripheral surface of the hub axle 420 is set to, for example, approximately 0.4 mm.

Moreover, the left clearance adjusting member 437 a and the right clearance adjusting member 437 b described above can be applied to the rear hub 412 as shown in FIG. 8 in accordance with the fifth embodiment of the present invention.

The rear hub 412 of the fifth embodiment comprises a hub axle 440, a hub body 441, a left bearing 442 a, a right bearing 442 b and a freewheel 443. The freewheel 443 is equipped with a drive unit 460 with a sprocket mounting section 460 a. The drive unit 460 is supported by the hub axle 40 so that the sprocket mounting section 460 a freely rotates around the hub axle 440. The sprocket mounting section 460 a is configured to be coupled to the multiple-layer sprocket 111 on the outer perimeter thereof as seen in FIG. 8. The freewheel 443 further includes a tubular part 462 that is non-rotatably mounted to the drive unit 460, and the one-way clutch 61 that is installed between the tubular part 462 and the hub body 421. The one-way clutch 61 is configured and arranged to transmit only the rotation of the direction of travel of the drive unit 460 to the hub body 421. A first freewheel bearing 463 and a second freewheel bearing 464 are mounted between the drive unit 460 and the hu axle 440. The first and second freewheel bearings 463 and 464 are arranged as a conventional sealed ball bearings that are well known in the art.

As seen in FIG. 8, the rear hub 412 of the fifth embodiment has a positional relationship of the hub body 441 and the left and right bearings 442 a and 442 b First that is similar to that of the front hub 410 shown in FIG. 7. Therefore, the clearance adjusting members 437 a and 437 b as explained above with reference to FIG. 7 can be utilized to prevent the grease from flowing out from the left and right bearings 442 a and 442 b in the rear hub 412 as shown in FIG. 8. Since the clearance adjusting members 437 a and 437 b are provided to both the left and right bearings 442 a and 442 b, the leakage of grease contained in the left and right bearings 442 a and 442 b can be prevented in the rear hub 412.

In the fifth embodiment as explained above, each of the clearance adjusting members has a generally cylindrical shape with a flange. Since the flange of the clearance adjusting member is mounted to the hub body and contacting the axial inner surface of the outer ring of the bearing, the clearance adjusting member can be mounted regardless of the size or shape of the outer ring of the bearing.

Accordingly, with the bicycle hub, as the hub body rotates along with the wheels in the direction of travel, grease contained in the bearing becomes fluid, and flows out from the bearings through the clearances between the outer rings and the hub axle. In particular, when a male screw is formed on the hub axle, the grease is more likely to flow out because of the pumping effect of the male screw. Thus, in the bicycle hub in accordance with the first to fifth embodiments of the present invention, the clearance adjusting member is disposed between the bearing and the hub axle to narrow the clearance between the outer ring of the bearing and the hub axle. The clearance adjusting members is disposed with respect to the outer ring of the bearing such that at least a portion of the clearance adjusting member is disposed axially inwardly of the outer ring.

Therefore, even when a male screw is formed on the hub axle, the leakage of grease from the bearing toward the axial inner direction of the hub axle can be prevented without deteriorating the smooth rotation of the bicycle hub.

The bearings in the present invention are arranged as an angular-type bearing with an outer ring and an inner ring. The outer ring of the bearing includes a ball receiving surface that faces in a generally axially outward direction, and the inner ring of the bearing includes a ball pushing surface that faces in a generally axially inward direction. Accordingly, with such angular-type bearings, the load capacity relative to the thrust force becomes larger, and the working face of the ball pushing surface (e.g., abutment state of the bearing surface and the bearing balls) can be adjusted by adjusting an axial position of the inner rings toward the axial inner direction.

As used herein, the following directional terms “forward, rearward, above, downward, vertical, horizontal, below and transverse” as well as any other similar directional terms refer to those directions of a bicycle equipped with the present invention. Accordingly, these terms, as utilized to describe the present invention should be interpreted relative to a bicycle equipped with the present invention.

According to the present invention, a clearance adjusting member is installed so as to narrow the clearance present between the outer rings and the hub axle in the inner axial direction of both outer rings, or at a minimum, of either one of the outer rings, thus narrowing the clearance between the outer rings and the hub axle. Therefore, even when a male screw is formed on the hub axle, the leakage of grease from the bearing towards the inner axial direction may be prevented.

The terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms should be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies.

While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims. Furthermore, the foregoing descriptions of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. 

1. A bicycle hub comprising: a tubular hub axle configured and arranged to be non-rotatably coupled to a bicycle; a hub body coaxially coupled on the hub axle so that the hub body is disposed radially outwardly with respect to the hub axle; a first bearing disposed between the hub body and the hub axle so that the hub body freely rotates with respect to the hub axle, the first bearing including a first outer ring coupled to the hub body, a first inner ring non-rotatably coupled to the hub axle in a position with respect to the first outer ring so that the first inner ring faces the first outer ring, and a plurality of first rolling components installed between the first outer ring and the first inner ring; and a clearance adjusting member disposed with respect to the first outer ring of the first bearing such that at least a portion of the clearance adjusting member is disposed axially inwardly of the first outer ring, the clearance adjusting member being configured and arranged to prevent a grease inside the first bearing to leak toward an axially inward direction of the hub axle with a prescribed radial clearance being maintained between the clearance adjusting member and one of the hub axle and the first outer ring of the first bearing.
 2. The bicycle hub as recited in claim 1, wherein the first outer ring of the first bearing includes a ball receiving surface that faces in a generally axially outward direction and the first inner ring of the first bearing includes a ball pushing surface that faces in a generally axially inward direction.
 3. The bicycle hub as recited in claim 1, wherein the clearance adjusting member has a generally cylindrical shape including a flange portion mounted on a radial inner surface of the hub body and contacting an axial inner surface of the first outer ring of the first bearing, and a cylindrical body portion extending from a radial inner section of the flange portion toward the axially inward direction of the hub axle as being spaced apart from the hub axle, the cylindrical body portion having a free end supported by the radial inner surface of the hub body.
 4. The bicycle hub as recited in claim 1, wherein the hub axle includes a male screw section extending on an entire outer peripheral surface of the hub axle, and the clearance adjusting member includes at least one O-ring mounted on the hub axle such that the prescribed radial clearance is formed between a radial outer surface of the O-ring and a radial inner surface of the first outer ring of the first bearing.
 5. The bicycle hub as recited in claim 1, wherein the hub axle includes a male screw extending on an entire outer peripheral surface of the hub axle, and the clearance adjusting member includes a cylindrical member mounted on the hub axle such that the prescribed radial clearance is formed between a radial outer surface of the cylindrical member and a radial inner surface of the first outer ring of the first bearing.
 6. The bicycle hub as recited in claim 5, wherein the clearance adjusting member is made of a synthesized resin with heat-contraction properties.
 7. The bicycle hub as recited in claim 1, further comprising a second bearing disposed between the hub body and the hub axle at an axial end portion of the bicycle hub that is axially spaced from the first bearing so that the hub body freely rotates with respect to the hub axle, the second bearing including a second outer ring coupled to the hub body, a second inner ring non-rotatably coupled to the hub axle in a position with respect to the second outer ring so that the second inner ring faces the second outer ring, and a plurality of second rolling components installed between the second outer ring and the second inner ring.
 8. The bicycle hub as recited in claim 7, wherein the clearance adjusting member has a generally cylindrical shape with a first axial end portion coupled to a radial inner surface of the first outer ring of the first bearing and a second axial end portion coupled to a radial inner surface of the second outer ring of the second bearing so that the prescribed radial clearance is formed between a radial inner surface of the clearance adjusting member and a radial outer surface of the hub axle.
 9. The bicycle hub as recited in claim 8, wherein the hub axle includes a male screw section disposed at least in a portion where the first inner ring is coupled to the hub axle.
 10. The bicycle hub as recited in claim 9, wherein the male screw section is arranged as a right-handed screw, the first bearing is installed on a right side of the hub axle when viewed in a direction of travel, and the clearance adjusting member has a right-handed female screw section on the radial inner surface thereof adjacent to the first bearing.
 11. The bicycle hub as recited in claim 1, further comprising a sprocket mounting section disposed in an axial end portion of the hub body that is axially spaced from the first bearing, the sprocket mounting section being configured and arranged to be coupled to at least one sprocket, and a freewheel configured and arranged to transmit a rotation of a crank of the bicycle only in a direction of travel to the hub body.
 12. The bicycle hub as recited in claim 11, further comprising a second bearing disposed between the hub body and the hub axle at an axial end portion of the bicycle hub that is axially spaced from the first bearing so that the hub body freely rotates with respect to the hub axle, the second bearing including a second outer ring coupled to the hub body, a second inner ring non-rotatably coupled to the hub axle in a position with respect to the second outer ring so that the second inner ring faces the second outer ring, and a plurality of second rolling components installed between the second outer ring and the second inner ring.
 13. The bicycle hub as recited in claim 12, wherein the hub body includes a hub main body portion with the first bearing disposed in an axial end portion thereof, and a generally cylindrical shaped power transmission member coupled in an axial end portion of the hub main body portion that is axially spaced apart from the first bearing with the second bearing disposed in an axial end portion of the power transmission member that is axially spaced from a coupling section between the power transmission member and the hub main body portion.
 14. The bicycle hub as recited in claim 13, wherein the freewheel includes a drive unit rotatably coupled to an outer peripheral surface of the power transmission member of the hub body with the sprocket mounting section being formed on an outer peripheral surface thereof, and a one-way clutch configured to transmit the rotation of the drive unit only in a direction of travel to the power transmission member of the hub body.
 15. The bicycle hub as recited in claim 14, wherein the clearance adjusting member has a generally cylindrical shape with a first axial end coupled to the radial inner surface of the first outer ring such that the prescribed radial clearance is formed between the radial inner surface of the first axial end of the cylindrical member and the outer peripheral surface of the hub axle, and a second axial end coupled to an inner peripheral surface of the hub body.
 16. The bicycle hub as recited in claim 14, wherein the clearance adjusting member is arranged such that the second axial end has a larger diameter than the first axial end and the diameter of the clearance adjusting member gradually becomes larger from the first axial end to the second axial end in a tapered manner.
 17. The bicycle hub as recited in claim 12, wherein the freewheel includes a drive unit rotatably coupled to the hub body with the sprocket mounting section being formed on an outer peripheral surface thereof, a tubular member non-rotatably coupled to the drive unit, and a one-way clutch disposed between the tubular member and the hub body configured and arranged to transmit the rotation of the drive unit only in a direction of travel to the hub body.
 18. The bicycle hub as recited in claim 17, further comprising an additional clearance adjusting member disposed with respect to the second outer ring of the second bearing such that at least a portion of the additional clearance adjusting member is disposed axially inwardly of the second outer ring, the additional clearance adjusting member being configured and arranged to prevent a grease inside the second bearing to leak toward an axially inward direction of the hub axle with the prescribed radial clearance being maintained between the additional clearance adjusting member and one of the hub axle and the second outer ring of the second bearing 